Evaluation of HLA-G 14 base-pair Insertion/ Deletion Polymorphism and Soluble HLA-G Level in Patients with Rheumatoid Arthritis in Mosul City: A Case-Control Study

Abstract

Background: HLA-G antigens are unconventional “class Ib” entities that are found on human leukocytes; they are essential in immunomodulation and regulation of inflammatory processes. Studies on the effects of the gene variations of HLA-G on rheumatoid arthritis have inconsistent results. Objective: To estimate the potential relationship between soluble HLA-G and the rs66554220 14 base-pair insertion/deletion polymorphism of HLA-G with disease activity parameters of rheumatoid patients in Iraqi patients. Methods: Using a DNA extraction kit, the genomic DNA was retrieved from 190 rheumatoid cases and 190 control individuals. Using primers for the HLA-G gene, the polymerase chain reaction was utilized for the genotyping of HLA-G 14ֺ base-pair insertion/deletion variants. The levels of soluble HLA-G were assessed by means of an ELISA test. Results: The results did not show a link between polymorphic HLA-G 14 base-pair insertion/deletion alleles and the possibility of getting rheumatoid disease. Serum levels of soluble HLA-G were substantially lower than those of controls (median=1.548 vs. median=7.391 U/mL), respectively. sHLA-G has a statistically substantial adverse link with ESR (r= -0.245, p<0.05). Furthermore, there are statistically substantial differences between the DAS-28 activity score and the sHLA-G level. Conclusion: There is no link between the risk of developing RA and polymorphic HLA-G 14 base-pair insertion or deletion in Iraqi patients. However, sHLA-G might serve as a diagnostic predictor of disease activity.